Question 1

Which of the following best explains why a single hormone can produce different effects in different target tissues?

Accepted Answer

Different target cells may have different receptors or signal transduction pathways for the same hormone.

Question 2

Which of the following is a correct sequence for a simple endocrine pathway regulating blood pH after a meal?

Accepted Answer

Stomach acid enters duodenum → duodenum secretes secretin → pancreas releases bicarbonate → blood pH increases

Question 3

Which hormone is released in response to low blood calcium ($$Ca^{2+}) $$levels, and what is one of its effects?

Accepted Answer

Parathyroid hormone (PTH); stimulates release of $$Ca^{2+}$$ from bones

Question 4

A patient presents with a goiter due to iodine deficiency. Which of the following best explains the physiological mechanism behind this condition?

Accepted Answer

Low iodine prevents thyroid hormone synthesis, leading to increased TSH secretion and thyroid gland enlargement.

Question 5

Which of the following is TRUE regarding the difference between water-soluble and lipid-soluble hormones?

Accepted Answer

Lipid-soluble hormones require transport proteins in the blood, while water-soluble hormones travel freely.

Question 6

Which hormone is primarily responsible for the 'fight-or-flight' response, and what is one of its effects?

Accepted Answer

Epinephrine; increases glucose and fatty acid release into the blood

Question 7

A researcher blocks the action of protein kinase A in liver cells. Which hormone's effect would be most directly impaired?

Accepted Answer

Epinephrine

Question 8

Which of the following best describes a negative feedback loop in hormone regulation?

Accepted Answer

The response reduces the initial stimulus.

Question 9

Which hormone is released from the posterior pituitary and is involved in milk secretion?

Accepted Answer

Oxytocin

Question 10

A patient has high blood glucose and low insulin levels. Which endocrine organ is most likely malfunctioning?

Accepted Answer

Pancreas

Question 11

Which of the following is a function of mineralocorticoids such as aldosterone?

Accepted Answer

Regulation of salt and water balance

Question 12

Which hormone is most directly involved in the regulation of biological rhythms such as sleep-wake cycles?

Accepted Answer

Melatonin

Question 13

Which of the following is an example of a hormone cascade pathway?

Accepted Answer

Hypothalamus releases TRH → anterior pituitary releases TSH → thyroid gland releases thyroid hormone

Question 14

Which of the following is a plausible effect of an endocrine disruptor that mimics estrogen?

Accepted Answer

Increased risk of reproductive abnormalities

Question 15

Which hormone is primarily responsible for stimulating the production of egg yolk proteins in female birds and frogs?

Accepted Answer

Estradiol

Question 16

Which of the following best describes the role of the hypothalamus in vertebrate endocrine regulation?

Accepted Answer

It integrates nervous and endocrine signals and regulates pituitary hormone release.

Question 17

Which hormone is secreted by the anterior pituitary and stimulates growth of bones and cartilage?

Accepted Answer

Growth hormone (GH)

Question 18

Which of the following is a correct statement about paracrine signaling?

Accepted Answer

It involves local regulators that act on nearby cells by diffusion.

Question 19

Which hormone is released by the adrenal cortex in response to long-term stress and influences glucose metabolism?

Accepted Answer

Cortisol

Question 20

A mutation causes a loss of function in the gene encoding the receptor for antidiuretic hormone (ADH). Which physiological effect would most likely be observed?

Accepted Answer

Inability to concentrate urine, leading to excessive water loss

Hormones and the Endocrine System: Regulation, Pathways, and Evolution

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